1. Field of the Invention
The present invention relates to a gear shifting completion determining device and a gear shifting completion determining method, and particularly to a technique of appropriately determining completion of gear shifting in a transmission in which the gear shifting is effected by an actuator, in accordance with an operating state of a vehicle.
2. Description of the Background Art
Conventionally, in a transmission having a gear train of constant mesh gears, a technique of selecting a gear by moving a sleeve by an actuator is known. In such a transmission, particularly at the time of gear shifting during the stopped state of the vehicle, there may occur a phenomenon where the sleeve and the gear are out of synchronization and thus they do not mesh with each other (hereinafter, also referred to as “uplock”). This means that gear shifting needs to be carried out taking account of the uplock.
Japanese Patent Laying-Open No. 2003-074684 discloses an automatic gear shifting completion determining device capable of avoiding uplock. The automatic gear shifting completion determining device described in Japanese Patent Laying-Open No. 2003-074684 includes: an automatic clutch automatically performing a clutch engaging operation by an actuator for the clutch; an automatic transmission connected to an engine via the automatic clutch, having an actuator for the transmission that shifts a sleeve arranged between a plurality of gears in an axial direction based on an operation of a shift lever, and automatically shifting a gear in response to the axial movement of the sleeve; and a control unit controlling the automatic clutch and the automatic transmission by driving the actuator for the clutch and the actuator for the transmission such that, when the sleeve and the gear are not synchronized while the engine is stopped and the sleeve cannot be moved in the axial direction for shifting to a gear required by the operation of the shift lever, i.e., when the uplock occurs, the gear is shifted to the required gear after the gear is shifted to a prescribed gear different from the required gear. Determination as to whether uplock has occurred or not is made based on a detection signal from a position sensor detecting the position of the sleeve.
According to the automatic gear shifting completion determining device described in the publication, in the event that the uplock occurs when the engine is stopped and thus it is not possible to shift to the gear required by the operation of the shift lever, the gear is set to a prescribed gear. With such shifting to the prescribed gear, “dislocation” is generated in the rotational direction between the gears for establishment of gear shifting to the required gear, which increases the possibility of avoiding the uplock. The gear is then set to the gear required by the operation of the shift lever under the condition that the possibility of avoiding the uplock is enlarged.
The hardware such as a gear train would suffer “deflection” by the load of the actuator, particularly upon occurrence of the uplock. With such “deflection”, even if the sleeve and the gear do not mesh with each other, the amount of stroke of the actuator may increase to the level where the sleeve and the gear would mesh in the absence of the “deflection”. Thus, it may be conceivable to determine completion of the gear shifting (occurrence of the uplock) based on the position of the sleeve or the stroke amount of the actuator taking account of the “deflection” of the hardware. In such a case, however, if there occurs no uplock or “deflection”, it may not be determined that the gear shifting has completed even if the sleeve has moved to the position where it can be said that the gear shifting has completed, leading to determination of completion of the gear shifting at an inappropriate timing later than the actual completion timing of the gear shifting.